Field of the Invention
The present invention relates to a structure of a check valve that can prevent water hammer and mechanical vibration.
Description of the Related Art
A check valve is, for example, arranged at a downstream side etc. of a pump, and is opened by a pump pressure to flow a fluid to the downstream side. In addition, when the pump stops, the check valve blocks a flow path by a biasing force of a spring provided at the valve.
As one example, a check valve of Japanese Patent Laid-Open No. 2005-36889 has been proposed.
Such check valve includes: a valve; a shaft support member that also functions as a valve seat; and a valve box that is fitted thereonto, and has a structure of preventing water hammer by quick spring movement. Namely, a built-in spring pushes down the valve vertically to the flow path, and thereby the flow path is quickly blocked.
This structure of the check valve, as shown in FIG. 13, has the valve box formed of a casting formed in a cylindrical shape, and the valve and the shaft support member that are arranged therein, and prevents water hammer at the time of valve closing as much as possible. However, the cylindrical valve box formed of the casting has heavy weight, and is structurally expensive.
In addition, the shaft support member of the valve is screw-fastened to both openings of the valve box. Therefore, there were disadvantages in which manufacturing processes, such as grooving of a screwing part, increased, the number of components also increased, and too much cost was required. Furthermore, the valve and the shaft support member must be screw-fastened when attached to the valve box, which is accompanied by troublesomeness.
Consequently, the present invention aims at providing a structure of a check valve that is simple and readily attachable to overcome these disadvantages with lower manufacturing cost.